<!--
 * @Description: 
 * @Author: liuzl
 * @Date: 2024-11-11 15:17:53
 * @LastEditors: liuzl
 * @LastEditTime: 2024-11-11 15:25:37
-->
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>17-事件案例</title>
</head>
<body>
<img id="light" src="js/img/off.gif"> <br>
<input type="button" value="点亮" onclick="on()">
<input type="button" value="熄灭" onclick="off()">
<br> <br>
<input type="text" id="name" value="BRIUP" onfocus="lower()"
onblur="upper()">
<br> <br>
<input type="checkbox" name="hobby"> 电影
<input type="checkbox" name="hobby"> 旅游
<input type="checkbox" name="hobby"> 游戏
<br>
<input type="button" value="全选" onclick="checkAll()">
<input type="button" value="反选" onclick="reverse()">
</body>
<script>
//1. 点击 "点亮" 按钮, 点亮灯泡;
// 点击 "熄灭" 按钮, 熄灭灯泡; -- onclick
function on(){
//a. 获取img元素对象
var img = document.getElementById("light");
//b. 设置src属性
img.src = "js/img/on.gif";
}
function off(){
//a. 获取img元素对象
var img = document.getElementById("light");
//b. 设置src属性
img.src = "js/img/off.gif";
}
//2. 输入框聚焦后, 展示小写;
// 输入框离焦后, 展示大写; -- onfocus, onblur
function lower(){ //小写
//a. 获取输入框元素对象
var input = document.getElementById("name");
//b. 将值转为小写
input.value = input.value.toLowerCase();
}
function upper(){ //大写
//a. 获取输入框元素对象
var input = document.getElementById("name");
//b. 将值转为大写
input.value = input.value.toUpperCase();
}
//3. 点击"全选"按钮使所有的复选框呈现选中状态;
// 点击"反选"按钮使所有的复选框选中状态取反;
function checkAll(){
//a. 获取所有复选框元素对象
var hobbys = document.getElementsByName("hobby");
//b. 设置选中状态
for (let i = 0; i < hobbys.length; i++) {
const element = hobbys[i];
element.checked = true;
}
}
function reverse(){
//a. 获取所有复选框元素对象
var hobbys = document.getElementsByName("hobby");
//b. 反转其选中状态
for (let i = 0; i < hobbys.length; i++) {
const element = hobbys[i];
if(element.checked)
element.checked = false;
else
element.checked = true;
}
}
</script>
</html>